Measurement of the stresses on a railway bogie is essential for monitoring the state of wear of the rolling stock and carrying out maintenance operations only when it is necessary. In fact, maintenance operations are costly and require stoppage times that reduce the profits linked to the use of the rolling stock. However, maintenance operations are of extreme importance for preventing failure or damage when the train is in use. Consequently, it is very important to apply reliable diagnostic methods for establishing the conditions of the rolling stock and programming maintenance operations in an efficient way such as to reduce the costs of management of the rolling stock itself.
In particular, carriages of a passenger train are electrified and it is thus possible to instrument the bogie with sensors and transmitters supplied by the line current. Instead, wagons of a freight train are not connected to the electrical supply, and the on-board diagnostic instrumentation requires installation of supply and data-transmission wiring starting from the locomotive and proceeding along the entire train. Said diagnostic system is clearly costly and also requires a complex maintenance since, in the case of malfunctioning and in particular of an interruption of the electrical contact, it is necessary to carry out testing on the wiring along the entire train.
In addition, railway trains, and in particular freight trains, are subject to severe standards, which restrict the possibilities of modifying the wagons. In particular, installation of measuring instrumentation on the bogie is normally not allowed without a rehomologation, which requires high costs of execution and long stoppage times.
From the production standpoint, the need is felt to provide a measuring bolt that can dimensionally replace current bolts present in an axle-box and having an internal structure suitable for reducing the production costs. At the same time, it is necessary to respect the stringent constraints of space imposed by the size of the bolts. In particular, it is necessary to identify an optimized position of each component in order to produce the energy sufficient for operation of the electronic and wireless-transmission devices mounted on the bolt.